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Comparison of different rates of artificial ventilation for preterm infants ventilated beyond the first week of life
V Chan1, A Greenough, M F Hird
1Dept of Child Health, King's College Hospital, London, U.K.
Insights
Increasing mechanical ventilator rates above 60 breaths per minute (bpm) offers no significant benefit for oxygenation in preterm infants beyond the first week of life. While 60 bpm improved carbon dioxide levels, higher rates did not.
Area of Science:
- Neonatal Medicine
- Pediatric Critical Care
- Respiratory Physiology
Background:
- Mechanical ventilation is crucial for preterm infants with respiratory distress.
- Optimizing ventilator settings is essential to minimize complications and improve outcomes.
- The impact of varying ventilator rates on blood gases in preterm infants beyond the neonatal period requires further investigation.
Purpose of the Study:
- To assess the effect of different mechanical ventilator rates on blood gas parameters in preterm infants.
- To determine the optimal ventilator rate for improving gas exchange in this vulnerable population.
Main Methods:
- Seventeen preterm infants (median gestational age 25 weeks) were studied at a median postnatal age of 11 days.
- Infants underwent ventilation at sequential rates of 30, 60, 30, 100, and 30 breaths per minute (bpm), each for 20 minutes.
- Peak inspiratory pressure, positive end-expiratory pressure, and I:E ratio were kept constant, with mean airway pressure adjusted via flow changes.
Main Results:
- No significant changes in oxygenation were observed at 60 bpm or 100 bpm compared to 30 bpm.
- A significant reduction in PaCO2 (partial pressure of carbon dioxide) was noted at 60 bpm versus 30 bpm (P < 0.001).
- This improvement in PaCO2 was not observed when the ventilator rate was increased to 100 bpm.
Conclusions:
- Increasing mechanical ventilator rates beyond 60 bpm does not appear to offer additional advantages for oxygenation in preterm infants ventilated after the first week of life.
- A ventilator rate of 60 bpm may be more effective in managing PaCO2 levels compared to lower rates in this patient group.
- Further research may explore individualized ventilator strategies based on specific infant needs and responses.
Abstract:
The effect on blood gases of different ventilator rates in preterm infants ventilated beyond the first week of life was assessed. Seventeen infants, median gestational age 25 weeks, were studied at median postnatal age of 11 days. The infants were ventilated through a set sequence of rates: 30, 60, 30, 100 and 30 breaths per min (bpm), each rate being maintained for 20 min. Peak and positive end expiratory pressure and I:E ratio (1:1) were unchanged at each rate and mean airway pressure was kept constant by altering flow as necessary. No significant change in oxygenation was demonstrated at either rates of 60 or 100 bpm compared to 30 bpm. PaCO2 levels were, however, significantly reduced at 60 bpm (P less than 0.001) compared to 30 bpm; but this improvement in PaCO2 was not seen at 100 bpm. These results suggest that increasing ventilator rate higher than 60 bpm in the majority of infants ventilated after the first week of life is not advantageous.